MB-43205: Introduce the allow_sanitize_value_in_deletion config param

This is a renaming of the previous allow_del_with_meta_prune_user_data
config param.

As per its old name, that was a switch for enabling/disabling
del_with_meta operating in "sanitizer" mode rather than enforcing a
strict validation and failing the operation in the case of invalid
payload.
Now we want to extend the same behaviour to DCP_DELETE/DCP_PREPARE.

That is because in 6.6.0 we have introduced some stricter validation
on deletion payloads that may fail the operation. That may happen
mainly in the case of pre-6.6 to 6.6 offline upgrade.

Under this MB we want to introduce the possibility to set a replica
in "sanitizer" mode, the same as we already do at del_with_meta. That
way, DCP_DELETE/DCP_PREPARE will just remove any invalid body in the
payload rather that failing.

Change-Id: Ia9faff48de3a51a77d367961b45c41ed45c609d1
Reviewed-on: http://review.couchbase.org/c/kv_engine/+/143656
Well-Formed: Build Bot <build@couchbase.com>
Tested-by: Paolo Cocchi <paolo.cocchi@couchbase.com>
Tested-by: Build Bot <build@couchbase.com>
Reviewed-by: Dave Rigby <daver@couchbase.com>

engines/ep/configuration.json

@@ -1,8 +1,8 @@
 {
     "params": {
-        "allow_del_with_meta_prune_user_data" : {
+        "allow_sanitize_value_in_deletion" : {
             "default" : "true",
-            "descr": "Let del_with_meta prune user data provided from the user instead of failing",
+            "descr": "Let EPE delete/prepare/del_with_meta prune any invalid body in the payload instead of failing",
             "dynamic" : true,
             "type" : "bool"
         },

engines/ep/src/ep_engine.cc

@@ -744,8 +744,8 @@ cb::mcbp::Status EventuallyPersistentEngine::setFlushParam(
             getConfiguration().setCouchstoreWriteValidation(cb_stob(val));
         } else if (key == "couchstore_mprotect") {
             getConfiguration().setCouchstoreMprotect(cb_stob(val));
-        } else if (key == "allow_del_with_meta_prune_user_data") {
-            getConfiguration().setAllowDelWithMetaPruneUserData(cb_stob(val));
+        } else if (key == "allow_sanitize_value_in_deletion") {
+            getConfiguration().setAllowSanitizeValueInDeletion(cb_stob(val));
         } else {
             msg = "Unknown config param";
             rv = cb::mcbp::Status::KeyEnoent;
@@ -2051,8 +2051,8 @@ class EpEngineValueChangeListener : public ValueChangedListener {
     }
 
     void booleanValueChanged(const std::string& key, bool b) override {
-        if (key == "allow_del_with_meta_prune_user_data") {
-            engine.allowDelWithMetaPruneUserData.store(b);
+        if (key == "allow_sanitize_value_in_deletion") {
+            engine.allowSanitizeValueInDeletion.store(b);
         }
     }
 
@@ -2139,10 +2139,10 @@ ENGINE_ERROR_CODE EventuallyPersistentEngine::initialize(const char* config) {
             "getl_max_timeout",
             std::make_unique<EpEngineValueChangeListener>(*this));
 
-    allowDelWithMetaPruneUserData.store(
-            configuration.isAllowDelWithMetaPruneUserData());
+    allowSanitizeValueInDeletion.store(
+            configuration.isAllowSanitizeValueInDeletion());
     configuration.addValueChangedListener(
-            "allow_del_with_meta_prune_user_data",
+            "allow_sanitize_value_in_deletion",
             std::make_unique<EpEngineValueChangeListener>(*this));
 
     auto numShards = configuration.getMaxNumShards();
@@ -5554,7 +5554,7 @@ ENGINE_ERROR_CODE EventuallyPersistentEngine::deleteWithMeta(
             datatype &= ~PROTOCOL_BINARY_DATATYPE_SNAPPY;
         }
 
-        if (allowDelWithMetaPruneUserData) {
+        if (allowSanitizeValueInDeletion) {
             if (mcbp::datatype::is_xattr(datatype)) {
                 // Whatever we have in the value, just keep Xattrs
                 const auto valBuffer = cb::const_char_buffer{

engines/ep/src/ep_engine.h

@@ -1161,5 +1161,12 @@ class EventuallyPersistentEngine : public EngineIface, public DcpIface {
     EpEngineTaskable taskable;
     std::atomic<BucketCompressionMode> compressionMode;
     std::atomic<float> minCompressionRatio;
-    std::atomic_bool allowDelWithMetaPruneUserData;
+
+    /**
+     * Whether del-operations at EPE level (currently only DelWithMeta) should
+     * just sanitize invalid payloads or fail the operation if an invalid
+     * payload is detected.
+     * Non-const as the related configuration param is dynamic.
+     */
+    std::atomic_bool allowSanitizeValueInDeletion;
 };

engines/ep/tests/ep_testsuite.cc

@@ -6961,7 +6961,7 @@ static enum test_result test_mb19687_fixed(EngineIface* h) {
             {"info", {"info"}},
             {"allocator", {"detailed"}},
             {"config",
-             {"ep_allow_del_with_meta_prune_user_data",
+             {"ep_allow_sanitize_value_in_deletion",
               "ep_backend",
               "ep_backfill_mem_threshold",
               "ep_bfilter_enabled",
@@ -7131,7 +7131,7 @@ static enum test_result test_mb19687_fixed(EngineIface* h) {
               "vb_0:num_entries",
               "vb_0:num_erroneous_entries_erased"}},
             {"", // Note: we convert empty to a null to get engine stats
-             {"ep_allow_del_with_meta_prune_user_data",
+             {"ep_allow_sanitize_value_in_deletion",
               "bytes",
               "curr_items",
               "curr_items_tot",

engines/ep/tests/mock/mock_synchronous_ep_engine.cc

@@ -75,8 +75,8 @@ SynchronousEPEngine::SynchronousEPEngine(std::string extra_config)
     maxItemSize = configuration.getMaxItemSize();
 
     setCompressionMode(configuration.getCompressionMode());
-    allowDelWithMetaPruneUserData =
-            configuration.isAllowDelWithMetaPruneUserData();
+    allowSanitizeValueInDeletion =
+            configuration.isAllowSanitizeValueInDeletion();
 }
 
 void SynchronousEPEngine::setKVBucket(std::unique_ptr<KVBucket> store) {

engines/ep/tests/module_tests/evp_store_with_meta.cc

@@ -42,7 +42,7 @@ class WithMetaTest : public SingleThreadedEPBucketTest {
         if (!config_string.empty()) {
             config_string += ";";
         }
-        config_string += "allow_del_with_meta_prune_user_data=true";
+        config_string += "allow_sanitize_value_in_deletion=true";
         SingleThreadedEPBucketTest::SetUp();
         store->setVBucketState(vbid, vbucket_state_active);
         expiry = ep_real_time() + 31557600; // +1 year in seconds

tests/testapp/testapp_withmeta.cc

@@ -216,7 +216,7 @@ TEST_P(WithMetaTest, MB36321_DeleteWithMetaRefuseUserXattrs) {
         conn.selectBucket(bucketName);
         const auto setParam = BinprotSetParamCommand(
                 cb::mcbp::request::SetParamPayload::Type::Flush,
-                "allow_del_with_meta_prune_user_data",
+                "allow_sanitize_value_in_deletion",
                 "false");
         const auto resp = BinprotMutationResponse(conn.execute(setParam));
         ASSERT_EQ(cb::mcbp::Status::Success, resp.getStatus());
@@ -292,7 +292,7 @@ void WithMetaTest::testDeleteWithMetaAcceptsUserXattrs(bool allowValuePruning,
         conn.selectBucket(bucketName);
         const auto setParam = BinprotSetParamCommand(
                 cb::mcbp::request::SetParamPayload::Type::Flush,
-                "allow_del_with_meta_prune_user_data",
+                "allow_sanitize_value_in_deletion",
                 allowValuePruning ? "true" : "false");
         const auto resp = BinprotMutationResponse(conn.execute(setParam));
         ASSERT_EQ(cb::mcbp::Status::Success, resp.getStatus());
@@ -356,7 +356,7 @@ void WithMetaTest::testDeleteWithMetaRejectsBody(bool allowValuePruning,
         conn.selectBucket(bucketName);
         const auto setParam = BinprotSetParamCommand(
                 cb::mcbp::request::SetParamPayload::Type::Flush,
-                "allow_del_with_meta_prune_user_data",
+                "allow_sanitize_value_in_deletion",
                 allowValuePruning ? "true" : "false");
         const auto resp = BinprotMutationResponse(conn.execute(setParam));
         ASSERT_EQ(cb::mcbp::Status::Success, resp.getStatus());